A portion of the disclosure of this patent document contains material to which a claim of copy right protection is made. The copyright owner has no objection to the facsimile reproduction of any one of the patent documents or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent file or records, but reserves all other rights whatsoever.
CRT devices particularly of the multi-phosphor gun type require a number of settings for variables such as white balance (R, G, B screen controls), black balance (R, G, B bias controls), contrast and black level (brightness) which ultimately determine the CRT's light response to an input signal. In U.S. Pat. No. 3,962,722 entitled "Color Television Setup Apparatus and Method" by W. S. Ciciora there is disclosed a factory production-line system for the adjustment of controls on television receivers to obtain consistent CRT output. Test patterns are displayed on the CRT screen and are measured by photosensitive devices at the system input. The outputs of the system are connected to bidirectional motors temporarily attached to the shafts of the controls of the receiver to adjust the controls as a function of the light measurements. Prior to the aforementioned patented invention, the adjustment of the various controls was performed by an operator in response to a "go", "no-go group" of lights which received inputs from the face of the CRT. Two additional patents of interest are U.S. Pat. No. 4,700,218 entitled "Automated System for Adjustment of the White Balance in a Signal Displayed on the Screen of a Color Cathode Ray Tube", by P. N. Thomsen et al. and U.S. Pat. No. 4,706,108 entitled "Automatic Setup System for Controlling Color Gain, Hue and White Balance of TV Monitor" by T. Kumagai et al. Both of the inventions covered in the adjustment of some CRT device parameters in accordance with stored reference values. The stored values are then used to provide adjustment signals for automatically adjusting one or more of the controls associated with the CRT to bring the value of the control to some predetermined standard value.
Another patent of interest is U.S. Pat. No. 4,415,921 entitled "Automatic Calibration System for Video Displays in Vision Testing" by P. Mulvanny et al. The method of that patent relates to a procedure for calibrating a video display to obtain a desired light level in response to an input level. Of main concern is the ability to repeatably adjust to the selected values of brightness and contrast. One of the prime uses of the invention is to provide a degree of standardization to vision tests in order to provide statistically constant data that can be utilized to detect vision problems.